| Summary: | 博士 === 國立中興大學 === 植物學研究所 === 78 === wildfere is an important factor disturbing forest ecosystems. The effects of wildfire an Taiwan red-pine forest, Taiwan acacia forest, monsoon forest, alpine grassland and Pandanus shrub were studied. Results obtained are summarized as follows:
1.Forest fire occurred frequently in the dry season, especially
at Taiwan red-pine forest and Pandanus shrub community.
During 1967~1988, 706 fires occurred and 127,647.73 hectares
were burned. During the past 10 yrars, The frequency of fires
caused by illegal farming decreased, but those caused by
campfire and unknown reasons increased.
2.Dre to crown opening and albedo effect, the highest daytime
temperature at surface soil increased up to 16.2＠ after
burning.
3.Post-fire runoff and erosion increased resulted from the
decrease of soilporosity and crown interception as will as
the consumption of litter layer. During the first rainy
season after fire at Tou-mou Mt., runoff increased by 45% and
170 （圖表省略） /ha surface soil was eroded.
4.Abundant nutrients were released form litter layer and plant
body after been burning. Both available nutrients and soil pH
value were increased after burning.
5.Mortality of pine trees by fire was 50~100%, but it was only
1~19% for hardwoods due to their vigorous sprouting ability
Mortality rate. For survived hardwoods,60~90% showed basal
sprouting; the others showed epicorrmic growth.
6.Flowering, fruiting and spore-bearing were enhanced after
fire due to the increase of nutrient availability, lighy
radiation and soil temperature fluctuation.
Following burning, spore-bearing indivedual of Brainea
insignis increased by 23 times; spikelet number of
Lophatherum gracile increased by 1.7 times.
7.Natural seedlings of shade-intolerant Pinus taiwanensis,
Crassocephalum crepidioides, Brainea insignis, etc., were
abundant following burning. Periodic fires might be
beneficial for the subsistence of rare Brainea insignis.
8.It is suggested that, Taiwan red-pine forest and alpine
grassland are fire-dependent communities. Pinus taiwanensis,
Miscanthus spp., Pteridium aquilinum subsp.wightianum, and
Yushania niitakayamensis cam accumulate abundant fuel and
induce the occurence of fires and thus maintaining their
dominance. Most fires in Taiwan acacia forest and monsoon
forest were incidently man-caused or burned for certain
purpose. These two forest types ane not fire-dependent
communities. The Pandanus shrub at coastal area could be
considered as intermediate to resist. wildfires.
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